Correct Answer : Pressure and shear stress
Explanation : When a body is kept in a stream of fluid flowing over it, there are two forces exerted. One is the pressure distribution and the other is the shear stress distribution. This leads to formation of lift or drag.
Correct Answer : False
Explanation : When the gas flows through the engine, there is a distribution of pressure and shear stress over all the components of the engine – compressor blades, turbine blades, combustion chamber and nozzle. This leads to the thrust formation.
Correct Answer : Change in momentum
Explanation : The thrust is caused due to the difference in momentum of the air which leaves from the exhaust and the one that enters the engine. There is a presence of pressure difference between exhaust and the inlet which causes thrust.
Correct Answer : Negative
Explaination : The sign of the integral ∫dS in the momentum equation is determined by the area of exhaust and inlet. When the exit area is less than the inlet area, the sum of negative components of pressure is more than the sum of positive components of the pressure. Thus, the sign becomes negative.
Explanation : In real life scenario, computing the thrust of the jet engine using theoretical and experimental results can be very exhaustive. The data obtained is not just extensive but also complex. Thus, to replace this, an integral form of momentum equation is used which gives the result much more accurately.
Correct Answer : True
Explanation : The integral form of conservative equation finds use in many practical scenarios such as finding thrust of a jet propulsion device – engine. It can be used to find out the thrust of turbojet, turboprop, ramjet, turbofan, rocket engine and many more.
Correct Answer : 71 kN
Explaination :
